Property tax in Los Alamos County, New Mexico
The median property tax bill in Los Alamos County, New Mexico is $2,717 a year, which is about 0.55% of the county's median home value of $495,800. That effective rate is about the same as the typical New Mexico county (0.55%) and lower than the national median (0.81%). These are American Community Survey 5-year estimates (2024); your own bill depends on your home's assessed value and any exemptions.
Estimate the property tax on a home in Los Alamos County
Enter a home's market value for a ballpark at Los Alamos County's average effective rate of 0.55% (Census). The real bill depends on the home's assessed value, the millage where it sits and any exemptions.
Estimated property tax: $2,727 / year
Property tax in Los Alamos County at a glance
| Measure | Value |
|---|---|
| Median annual property tax | $2,717 |
| Median home value | $495,800 |
| Effective tax rate | 0.55% |
| Typical New Mexico county rate | 0.55% |
| National median county rate | 0.81% |
Effective rate = median real estate taxes paid divided by median home value. Source: U.S. Census Bureau, American Community Survey 5-year estimates.
How does Los Alamos County compare in New Mexico?
Among New Mexico's 33 counties, Los Alamos County has the 16th highest effective property-tax rate: 15 rank higher and 17 rank lower. That is near the middle for New Mexico. Nationally, it ranks 2459th of 3135 US counties by effective rate. See every New Mexico county ranked.
How much do homeowners in Los Alamos County actually pay?
The median is only the middle bill. Across Los Alamos County's 6,171 owner-occupied homes, 40.4% pay $3,000 or more a year in property tax, 67.6% pay at least $2,000, and 3.3% pay under $800. Another 3.8% report paying no property tax at all, which usually means an exemption covers the whole bill.
| Annual bill | Homes | Share |
|---|---|---|
| Under $800 | 201 | 3.3% |
| $800 to $1,499 | 827 | 13.4% |
| $1,500 to $1,999 | 739 | 12% |
| $2,000 to $2,999 | 1,676 | 27.2% |
| $3,000 or more | 2,493 | 40.4% |
| No property tax paid | 235 | 3.8% |
Owners with a mortgage pay a median of $2,755 and owners without one pay $2,645. That is within 10% either way, so in Los Alamos County paying off the house does not go with a noticeably different bill. Census table B25103.
How does the Los Alamos County property tax bill compare with local incomes?
The median property tax bill of $2,717 is about 1.7% of the median income of Los Alamos County homeowner households, $161,791 a year. That compares two middles, so a retiree in a long-held home can pay a far larger share. 74.8% of Los Alamos County's occupied homes are lived in by their owners; renters pay property tax too, just folded into rent.
Have property taxes gone up in Los Alamos County?
Yes. The median bill went from $1,997 in 2015-2019 to $2,717 in 2020-2024, a 36.1% rise. Over the same span the median home value moved 63.7%, from $302,800 to $495,800. Bills rose more slowly than values, which is what assessment caps and falling millage rates do: the county is taxing a smaller share of each home's worth.
Two Census ACS 5-year periods with no survey years in common, in each period's own dollars. A change counts only if it exceeds the combined 90% margin of error.
Property tax in counties next to Los Alamos County
Los Alamos County borders 3 counties.
| County | Effective rate | Median bill | Median home value |
|---|---|---|---|
| Sandoval County, NM | 0.73% | $2,296 | $313,800 |
| Los Alamos County, NM (this county) | 0.55% | $2,717 | $495,800 |
| Santa Fe County, NM | 0.48% | $2,152 | $446,300 |
| Rio Arriba County, NM | 0.42% | $1,021 | $243,700 |
How is a home assessed in Los Alamos County?
New Mexico assesses homes at 33.33% of market value in every county, Los Alamos County included. How New Mexico assesses and reappraises homes.
Is there a homestead exemption in Los Alamos County?
Yes, for a head of family. New Mexico's exemption takes $2,000 off taxable value, often saving $50 to $90 a year. That is the New Mexico rule, and it applies in Los Alamos County. New Mexico's exemptions and relief programs in full.
When are property taxes due in Los Alamos County?
County treasurers mail bills around November 1. Tax is payable in two equal installments, the first due November 10 and the second due April 10 of the following year. You get a one month grace period on each: interest starts if the first half is not paid by December 10 or the second half by May 10.
New Mexico splits the bill into 2 installments. That is the New Mexico rule. Los Alamos County issues and collects the bill, so the dates printed on your statement are the ones that bind you.
How to appeal your Los Alamos County property assessment
You contest the assessed value with the the county valuation protests board, reached by petitioning the county assessor. The filing deadline is typically 30 days after the assessor mails your notice of valuation. That is the New Mexico rule; Los Alamos County sets the exact dates and forms. The New Mexico appeal process step by step.
New Mexico rules from primary state sources, reviewed September 7, 2026; sources on the New Mexico page.
Work out your own numbers
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How much house can I afford?
Your income, debts and down payment against the 28/36 rule lenders actually use, with Los Alamos County's tax rate to hand.
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Mortgage calculator
Monthly payment with principal, interest, tax and insurance, plus what an extra payment saves you.
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New Mexico income tax
Brackets, standard deduction and what New Mexico actually taxes.
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Sales tax in Los Alamos County
The other local tax: combined state and local rate for this county.
Sources
- Median real estate taxes paid and median home value for Los Alamos County, New Mexico: U.S. Census Bureau, American Community Survey 5-year estimates (2020-2024), tables B25103, B25077, B25102, B25119 and B25003; the five-year comparison uses the 2015-2019 estimates. Neighboring counties: Census county adjacency file.